docs: def setup_argparse(self, argument_parser):
      """Set up custom arguments needed for this profile."""
      import glob
      import logging
      import argparse
  
      def get_fonts(pattern):
  
        fonts_to_check = []
        # use glob.glob to accept *.ufo
  
        for fullpath in glob.glob(pattern):
          fullpath_absolute = os.path.abspath(fullpath)
          if fullpath_absolute.lower().endswith(".ufo") and os.path.isdir(
              fullpath_absolute):
            fonts_to_check.append(fullpath)
          else:
            logging.warning(
                ("Skipping '{}' as it does not seem "
                 "to be valid UFO source directory.").format(fullpath))
        return fonts_to_check
  
      class MergeAction(argparse.Action):
  
        def __call__(self, parser, namespace, values, option_string=None):
          target = [item for l in values for item in l]
          setattr(namespace, self.dest, target)
  
      argument_parser.add_argument(
          'fonts',
          # To allow optional commands like "-L" to work without other input
          # files:
          nargs='*',
          type=get_fonts,
          action=MergeAction,
          help='font file path(s) to check.'
          ' Wildcards like *.ufo are allowed.')
  
      return ('fonts',)